The present invention relates to a device for locking lightbulbs in their sockets.
Theft of lightbulbs has long been a problem. When lightbulbs were first introduced, due to their high cost and novelty, they were often pilfered. As a result of this, during the early 1900's, many attempts were made to develop a device for locking lightbulbs in their sockets. Exemplary of locking devices are those described in U.S. Pat. Nos. 740,248; 933,296; 934,760; 1,148,538; 1,187,330; 1,259,482; and 1,495,586.
Many of these prior art devices suffered from defects. For example, some merely relied on compression on the socket and bulb by means of a clamp. In many circumstances, the compression forces could be inadequate or could break the bulb. Another technique used was a ring around the socket with a locking screw in the ring extending through the socket and into direct engagement with the bulb as described in U.S. Pat. No. 933,296 to Davis.
After about 1920, with the advent of the mass-produced, low-priced lightbulb, interest in devices for preventing pilferage of lightbulbs decreased. However, high efficiency, long-life lightbulbs recently have been developed which are considerably more expensive than conventional incandescent lightbulbs. Among these new bulbs are fluorescent bulbs adapted to fit into a conventional incandescent holder. These new bulbs, because of their relatively high price, are the subject of theft. In view of this problem, there is a need for a locking device for the modern day lightbulb. Moreover, there is a need for a locking device that can be retrofitted to existing light sockets.